The present invention is directed on linking a pair of hearing devices to form a set of binaural hearing devices. Such hearing devices may be therapeutic hearing aid devices for hearing impaired persons or may be hearing devices just for improving human hearing or for allowing listening to electronically converted audio signals as e.g. for telephone ear-sets, ear-sets in airplanes or even noise protection hearing devices, thereby possibly for active noise cancellation.
Today known binaural links between a pair of hearing devices are impaired by the severe requirements at hearing devices and thereby especially at hearing aid devices with respect to electric power consumption. There has been proposed to establish such a binaural wireless communication link in the RF-frequency band or even in the microwave frequency band. Thereby satisfyingly small receiving and transmission aerials may be used, but the power consumption for the transmitter and the receiver is considerable.
A communication link approach at lower transmission frequencies necessitates, whenever audio signals shall be transmitted via such link, relatively complex encoding and decoding procedures as e.g. MPEG-codec, so as to result in high compression of the data being transmitted. Such encoding procedures nevertheless have the drawback of significant signal delay normally in excess of 50 msec and are therefore not suited for binaural communication between hearing devices as here a real-time signal processing is important.
Other approaches to such binaural communication are based on wire-bound transmission. This necessitates the appliance of at least two wires by mini plugs to both hearing devices of the pair. Handling of a cable with two wires and especially of respective mini-plugs at the hearing devices is cumbersome for the individual, especially if such handling is performed as the hearing devices are already applied to the individual's ear. Therefore it is an object of the present invention to propose a binaural communication link which eliminates the drawbacks mentioned of wire-based links.